Macromolecular Crowding Meets Tissue Engineering by Self‐Assembly: A Paradigm Shift in Regenerative Medicine

Abstract

MMC, the addition of inert polydispersed macromolecules in the culture media, effectively emulates the dense in vivo extracellular space, resulting in amplified deposition of ECM in vitro and subsequent production of cohesive, ECM-rich living substitutes.

Accelerated Development of Supramolecular Corneal Stromal-Like Assemblies from Corneal Fibroblasts in the Presence of Macromolecular Crowders

“…This is in accordance to previous studies that demonstrated that negatively charged macromolecules (e.g. DxS and CR) accelerate tissuespecific ECM deposition, recognising CR as the most effective crowder, due to its inherent polydispersity that achieves more effective volume occupancy / exclusion and thus higher ECM deposition (40). ICC analysis demonstrated that HCFs were negative for α SMA, CD34 and keratocan.…”

“…The medium was replaced after 24 h with fresh medium containing the optimum concentration of macromolecular crowders (100 µg/ml of DxS or 75 µg/ml of CR; both negatively charged) (40,41) with various concentrations of newborn calf serum (NBCS) or human serum (HS), ranging from 0.0 to 10 %. 100 µM L-ascorbic acid phosphate supplement was added in the medium to enhance collagen synthesis.…”

“…Although previous studies have demonstrated that the addition of inert macromolecules in the culture media, following the principles of excluding volume effect, increases the relative concentration of procollagen and proteinases, resulting in propeptide cleavage and subsequent accelerated ECM deposition in culture of skin and lung fibroblasts (38)(39)(40), there is no work todate on cells that are particularly susceptible to phenotypic drift, such as corneal fibroblasts.…”

The past, present and future in scaffold-based tendon treatments

“…Indeed, the addition of negatively charged macromolecules in the culture media (Figure 6), by imitating the naturally crowded in vivo context, dramatically accelerates the conversion of procollagen to collagen, resulting in a 30-to 80-fold increase in tissue-specific ECM deposition. Using human TCs, a rich in ECM and cohesive cell-sheet was produced with intact cell-cell and cell-ECM junctions as early as 6 days in culture, without any negative effects in TC functions [449]. Despite these advancements, a complete threedimensional tendon-equivalent has yet to be developed.…”

Recreating complex pathophysiologies in vitro with extracellular matrix surrogates for anticancer therapeutics screening

“…Further, such approaches require prolonged in vitro culture to develop a proper 3D model, which is often associated with cell phenotypic drift [137,138]. Although macromolecular crowding aspires to address this slow or delayed ECM deposition [139][140][141], this technology is still at the primitive stages and, for that reason, scaffoldbased technologies (e.g., hydrogels, fibres, sponges) are under intense investigation.…”